1. Field of the Invention
The present invention relates to the field of physical science, and in particular the field of magnetic resonance. More specifically, the invention concerns a process and an apparatus for measuring the characteristics of variation of the magnetic induction with respect to temperature.
2. Description of the Prior Art
In the prior art, the pulling process is widely used for determining the temperature parameter of a magnetic material, i.e. pulling a test coil at pre-set temperature. While the test sample is placed inside a silica tube in the test coil, the magnetic characteristic of the sample under this temperature is obtained and recorded through the process of pulling the test coil. A disadvantage of this measuring apparatus is that the pulling of the test coil has to be done identically each time, because the measurement precision of each sample is determined by the manual pulling speed of the operator. If the error of the pulling speed is relatively large, then the measurement precision will deviate notably, leading to the insurmountable disadvantage of huge manual operating errors of this apparatus. Furthermore, this measuring apparatus can test only one sample magnetic material each time (due to the limitations of manual pulling), thus using this measuring apparatus in the testing procedure results in problematic waste in time, money and energy. In addition, this measuring apparatus also has shortcomings like fragility and low reproducibility of the measurement results each time, etc.
Chinese Utility Model application No. 98241658.X, filed on Oct. 22, 1998 and entitled “Measuring Apparatus of the Temperature Parameter of Permanent Magnets”, discloses an apparatus with a heating furnace on a platform inside the magnet shielding mask. The sample chamber and the sample material are disposed in the furnace, while the furnace is enclosed by a cooling jacket and covered with an insulation cover. A probe and its support are fixed on the platform. The probe, the magnetometer and the drawing instrument are connected in series, with the thermocouple being connected to the drawing instrument. However, this apparatus has a relatively complicated structure, and a special apparatus is needed to measure the temperature parameter of the magnet sample and hence the cost is relatively high.
Magnetic materials like amorphous alloys are commonly used to achieve the homogeneous background magnetic field in current MRI (magnetic resonance imaging) systems. The providers of magnetic materials (e.g. amorphous alloys) seldom provide the temperature parameters of their product. To design the magnet of the MRI system and estimate its stability, it is important to obtain the temperature parameters of relevant magnetic materials.
For some manufacturers who make MRI systems, it is essential to obtain the temperature parameters of the permanent magnetic or ferromagnetic materials in their products. However, purchasing new equipments for obtaining the temperature parameter will increase the cost, and the measuring result is not very accurate.